In China, since around 2015, smartwatches have become widely used by schoolchildren. They are advertised on television throughout the country as a safety device whereby the child can call in case of emergency. The devices are commonly colorful and made of plastic. They normally have no display unless a button is pushed. These smartwatches have limited capability compared to other smartwatches; their main functions consist of being able to conduct calls, displaying of time, and sometimes have air temperature sensitivity. They cost around $100 to $200 USD.
Although rectangular is the most common design, there are smart watches that have a circular display similar to regular watches. The Apple Watch is only available in the rectangular design. The circular design is available in the Samsung Gear S2, Moto 360, and LG G Watch R models. Many models have changeable straps, so you can dress casual, sporty, and formal.
In June 2000, IBM displayed a prototype for a wristwatch that ran Linux. The original version had only 6 hours of battery life, which was later extended to 12.[20] It featured 8 MB of memory and ran Linux 2.2.[21] The device was later upgraded with an accelerometer, vibrating mechanism, and fingerprint sensor. IBM began to collaborate with Citizen Watch Co. to create the "WatchPad". The WatchPad 1.5 features a 320 × 240 QVGA monochrome touch sensitive display and runs Linux 2.4.[22][23] It also features calendar software, Bluetooth, 8 MB of RAM and 16 MB of flash memory.[24][25] Citizen was hoping to market the watch to students and businessmen, with a retail price of around $399.[25] Epson Seiko introduced their Chrono-bit wristwatch in September 2000. The Chrono-bit watches feature a rotating bezel for data input, synchronize PIM data via a serial cable, and can load custom watch faces.[26]

As of 4 September 2013, three new smartwatches have been launched: the Samsung Galaxy Gear, Sony SmartWatch 2,[62] and the Qualcomm Toq.[63] PHTL, a company based in Dallas, Texas, completed is crowd-funding process on Kickstarter for its HOT Watch smartwatch in September 2013. This device enables users to leave their handsets in their pockets, since it has a speaker for phone calls in both quiet and noisy environments.[64] In a September 2013 interview, Pebble founder Eric Migicovsky stated that his company was not interested in any acquisition offers,[65] but revealed in a November 2013 interview, that his company has sold 190,000 smartwatches, the majority of which were sold after its Kickstarter campaign closed.[60]

The Apple Watch Series 4 is now on sale, and it's the best smartwatch you can buy right now. The redesigned device, which starts at $399 for the GPS model and $499 for the cellular version, is the best smartwatch you can buy. It has a larger display and slightly bigger case size while retaining the same rounded square design the watch is known for. Even more importantly, Apple received FDA clearance for a new electrocardiogram feature that can take a 30-second EKG and diagnose atrial fibrillation.